The exception to careful planning is post breakup Russia. While at their best, Russians still excel at the undetectable murder, their reputation has been sullied by high profile embarrassments, amateurish exploits involving high tech poisons, such as the poisoning of Alexander Litvinenko, and the contamination of half of Salisbury with Novichok A-234. It suggests that, contrary to the almost automatic “Putin approved…” theory of assassinations, there are multiple entities in Russia that initiate, including the SVR, and multiple entities that execute, including possible freelancers.

Consider:

Litvinenko and the Skripals were attacked with the most sophisticated poisons known.

Zelimkhan Khangoshvili was shot by a Russian on a bicycle. Other Chechens have been assassinated by gun shot.

The personal characteristics of the victims are unrelated to the modes of attack. The mode is determined by the authority that requires it.